Small swing type shovel

ABSTRACT

The present small swing type excavator is characterized by comprising an engine ( 81 ) disposed in the rear section of a rotating frame ( 8 ) in such a condition that the longitudinal direction thereof is directed to the lateral direction of the rotating frame ( 8 ), a hydraulic oil tank ( 82 ) disposed on one lateral side in front of the engine ( 81 ), a cabin ( 83 ) disposed on the other lateral side, an air conditioner ( 85 ) disposed under a floor ( 84 ) of the cabin ( 83 ) and having two surfaces facing to, respectively, the front side and the left outer side of the rotating frame ( 8 ), and a fuel tank ( 86 ) formed so as to be arranged along at least two surfaces of the front and left side surfaces of the air conditioner ( 85 ) and detachably attached to the rotating frame ( 8 ).

TECHNICAL FIELD

The present invention relates to a small swing type excavator, whereinan upper rotating body rotates in such a condition that the rear endthereof hardly projects outside the width of a lower traveling body.

BACKGROUND ART

Among various types of a small hydraulic excavators, so-called smallswing type or short-radius excavator, wherein a rear end rotating radiusof an upper rotating body is set to about ½ of the width of a lowertraveling body, can rotate 360 degrees in such a condition that the rearend of the upper rotating body hardly projects outside the width of thelower traveling body, which is therefore suitable for work in narrowplaces such as urban work or subway work. In such a short-radiusexcavator as above, there is a severe restriction on the longitudinallength of the upper rotating body in comparison with common smallhydraulic excavators in which the rear end of the upper rotating bodyprojects outside the width of the lower traveling body when rotating,resulting in a reduction in arrangement space for devices, which makesit difficult to an employ device layouts in the common small hydraulicexcavators without change. Accordingly, in the art disclosed in, forexample, Japanese Patent Laid-Open Publication No. Hei. 11-269931, underthe floor of an operator seat covered by a canopy are disposed a fueltank and a battery to make effective use of the space under the floor.However, known short-radius excavators suffer from the followingproblems.

(1) Although it has become likely, in recent years, that cabin having asubstantially sealed structure adapted to shut out outside air isprovided to protect operators against outside noise, dust, etc. and thatair conditioner is provided to ensure habitability of the cabin, thereis no arrangement space for air conditioner in the case of short-radiusexcavators.

That is, in the case of large-sized machines, an air conditioner may beprovided in a seat stand as shown in the art disclosed in JapanesePatent Laid-Open Publication No. 2001-295319, while in the case ofshort-radius excavators, there may exist part of an engine under a seatstand, resulting in a difficulty in ensuring enough space in the seatstand.

Therefore, in conventional short-radius excavators, no air conditioneris provided or the volume of a fuel tank is sacrificed to provide an airconditioner as shown in the art disclosed in Japanese Patent Laid-OpenPublication No. Hei. 11-269931 above-mentioned, or an air conditioner ismounted on the ceiling of a cabin as shown in the art disclosed inJapanese Patent Laid-Open Publication No. Hei. 9-315138. However,sacrificing the volume of the fuel tank requires short fueling interval,resulting in poor operating efficiency. Also, in the case of mountingair conditioner on the ceiling of cabin, vehicle height is increased,resulting in poor carrying performance.

The present invention has been made in consideration of theabove-described circumstances and a first object thereof is to provide ashort-radius excavator, wherein the volume of a fuel tank is increasedas much as possible with ensuring of an arrangement space for airconditioner to allow effective use of the space in a rotating frame.

(2) Also, with respect to such a short-radius excavator as above, an artfor arranging an engine in a slanted manner is disclosed in, forexample, Japanese Patent Laid-Open Publication No. Hei. 5-125742. In theart, a hydraulic pump is connected to one side of an output shaft in thelongitudinal direction of the engine, while a cooling device is disposedat the other side. In front of the cooling device is disposed ahydraulic oil tank, and in front of the hydraulic pump and under thefloor is provided a control valve.

In such a configuration as above, the hydraulic pump and the hydraulicoil tank are wide apart from each other, which results in requiring alarge space on a rotating frame for the arrangement of suction pipesthat cannot be bent in small radius easily due to the bore thereofhaving the maximum value among all pipes. Also, providing the controlvalve under the floor suffers from a problem in that removal work forfloor plates, for example, is required to maintain the control valve,resulting in poor maintenance performance.

The present invention has been made in consideration of theabove-described circumstances and a second object thereof is to providea short-radius excavator, wherein problems that occur when arranging anengine in a slanted manner are overcome to allow effective use of thespace in a rotating frame.

(3) Moreover, in the case of short-radius excavators in which workingdevice is pivoted movably in the lateral and longitudinal directions ina protruding manner from the front end of upper rotating body, there isa little arrangement space for devices in the longitudinal direction andtherefore it is difficult to employ device layouts in common smallhydraulic excavators without change. In the art disclosed in JapanesePatent Laid-Open Publication No. Hei. 11-269931 above-mentioned, acontrol valve, etc. are disposed in the front part of a rotating frame,including the following disadvantages.

In front of the rotating frame is disposed a working device (composedof, for example, a boom, an arm, etc.), and when enlarging an upperrotating body forward to ensure an arrangement space for devices, thefront rotating radius increases, resulting in a disadvantage in terms ofdegree of freedom in, for example, excavating work using the workingdevice. In addition, in front of the upper rotating body is required alot of space to arrange pipes from the control valve on the upperrotating body through hydraulic actuators such as a hydraulic cylinderof the working device.

The present invention has been made in consideration of theabove-described circumstances and a third object thereof is to realizean device layout that makes effective use of the space in the widthdirection of a rotating frame of a short-radius excavator in which aworking device is pivoted movably in the lateral and longitudinaldirections in a protruding manner from the front end of the upperrotating body.

DISCLOSURE OF THE INVENTION

According to one aspect of the present invention, for achieving thefirst object above, there is provided a small swing type excavator,wherein an upper rotating body is mounted rotatably around a verticalshaft on a lower traveling body, rotating radius of a rear end of theupper rotating body being set to about one half of the width of thelower traveling body and devices being mounted on a rotating frame ofthe upper rotating body, characterized in that an operator cab isdisposed on one lateral side on the rotating frame, and that an airconditioner and a fuel tank are provided, respectively, on an inner andan outer side in the width direction of the excavator in a space under afloor of the operator cab, the fuel tank comprising an extension portionextending to at least the front surface side of the air conditioner. Itis noted that being set to about one half means that the rear end of therotating frame does not project outside the width of the lower travelingbody, or that projects only up to one half of the vehicle width +10%thereof (the same applies hereinafter).

In accordance with the above-described configuration, the operator cabis disposed on one lateral side on the rotating frame, and the airconditioner and the fuel tank are provided, respectively, on an innerand an outer side in the width direction of the excavator in the spaceunder the floor of the operator cab, the fuel tank comprising anextension portion extending to at least the front surface side of theair conditioner, whereby providing the large-sized fuel tank utilizingthe blank space, for example, in front of the air conditioner which hasnot been conventionally used, the volume of the fuel tank may beincreased with ensuring of an arrangement space for the air conditioner.It is noted that if including no heat source, plastic fuel tanks havinghigh-degree of freedom of machining shape have become employedfrequently in recent years. Therefore, employing these kinds of plasticfuel tanks allows easy formation even in the case of complicated shapescomprising extension portions.

Meanwhile, in the case of fuel tanks that are frequently filled with oilat work sites, there is a possibility that impurities (sand, mud, etc.)may be mixed thereinto when fueling, resulting in an accumulation of theimpurities at the bottom of the tanks with age. The accumulation of theimpurities blocks a fuel suction port for an engine as a motor, makingthe engine inoperative. Hence, it is preferable in the above-describedconfiguration that the fuel tank be detachably attached to the rotatingframe in such a condition that the extension portion extends along atleast the front surface side of the air conditioner, and that an openingportion capable of taking the fuel tank inside and outside therethroughbe provided in an outer peripheral wall of the rotating frame. In thiscase, when impurities accumulate at the bottom with age, the fuel tankmay be detached from the rotating frame to be cleaned on the outsidethereof before the engine as a motor becomes inoperative (engine down),and then the impurities accumulated at the bottom of the fuel tank canbe removed to prevent engine down. Meanwhile, in the unlikely event thatthe engine goes down, the fuel tank may be detached from the rotatingframe to be cleaned on the outside thereof, and then the impuritiesaccumulated at the bottom of the fuel tank can also be removed torestart the operation of the engine.

Also in the case an opening portion is provided in the outer peripheralwall of the rotating frame, there is a possibility, for example, thatsediments generated during construction work may get inside through theopening portion to accumulate around the fuel tank. Hence, it ispreferable that a cover portion adapted to cover the opening portion befurther provided in the outer peripheral wall of the rotating frame. Inthis case, since it becomes unlikely that sediments may get insidearound the fuel tank through the opening portion and the fuel tank canbe protected against unexpected direct hits by sediments, etc., theconfiguration above is suitable particularly for plastic tanks that havelow impact resistance compared to steel ones.

According to another aspect of the present invention,. for achieving thesecond object above, there is provided a small swing type excavator,wherein an upper rotating body is mounted rotatably around a verticalshaft on a lower traveling body, rotating radius of a rear end of theupper rotating body being set to about one half of the width of thelower traveling body and devices being mounted on a rotating frame ofthe upper rotating body, characterized in that a power source isdisposed in a rear section of the rotating frame in such a manner thatsaid power source laterally stretches long and both lateral ends of saidpower source are longitudinally shifted each other to be inclined; ahydraulic pump is disposed on one end side closer to the rear side ofboth the lateral ends of the power source, while a cooling device isdisposed on the other end side closer to the front side of both thelateral ends; a fuel tank is disposed in front of the hydraulic pumpthrough a predetermined space; and a hydraulic oil tank is disposed inthe predetermined space.

In accordance with the above-described configuration, the power sourceis disposed in the rear section of the rotating frame in such a mannerthat said power source laterally stretches long and both lateral ends ofsaid power source are longitudinally shifted each other to be inclinedwhereby it never occurs that most of the space in the rear section ofthe rotating frame of the upper rotating body is occupied only by thepower source. That is, although the shape of the power source isdetermined almost automatically to meet the function thereof, whenarranging the power source in such an inclined or slanted manner, acertain space (predetermined space) can be ensured in front of onelateral side from where the power source is moved backward away. In thiscase, it is possible, for example, to dispose a fuel tank havinghigh-degree of freedom of shape under the floor of an operator cabinstalled in front of the power source, and to dispose a large-sizedhydraulic oil tank in the blank space ensured as above. Thus, it ispossible to allow for the device arrangement in the rotating frame.

In addition, the hydraulic pump is disposed on one end side closer tothe rear side of both the lateral ends of the power source, while thecooling device is disposed on the other end side closer to the frontside; the fuel tank is disposed in front of the hydraulic pump through apredetermined space; and the hydraulic oil tank is disposed in thespace, whereby the amount of suction pipes on the rotating frame isreduced, and combined with the slanted arrangement of the power source,it is further possible to allow for the device arrangement in therotating frame.

It is preferable that the fuel tank be disposed on one end side across aswivel joint disposed at the center of rotation, while a control valvebe disposed on the other end side, the fuel tank and the control valvebeing in front of the power source. In this case, it is possible toarrange devices making effective use of the maximum width of therotating frame, where the volume of the fuel tank is ensured and themaintenance performance of the control valve is improved.

Further, it is preferable that an operator cab be disposed on the uppersurface on one lateral side of the rotating frame, and that the fueltank be arranged under the floor of the operator cab. In this case,other devices can be arranged high in the vehicle, whereby the layout isfacilitated.

It is preferable that the hydraulic oil tank be formed into a fan shapein such a manner that the hydraulic oil tank spreads outward from therotating frame when viewed vertically. In this case, the maximum volumeof the hydraulic oil tank can be obtained between the power sourcearranged in a slanted manner and the fuel tank (or operator cab).

It is preferable that the hydraulic oil tank be formed in such a mannerthat at least part thereof reaches to under the hydraulic pump. In thiscase, the volume of the fuel tank can be further increased.

It is preferable that the rotating frame comprise an opening portion formaintenance at the end on the side where the control valve and thecooling device are provided, and a cover portion adapted to cover theopening portion. In this case, the control valve and the cooling devicecan be maintained easily by opening the cover portion. Thus, devices canbe maintained easily if necessary.

According to still another aspect of the present invention, forachieving the third object above, there is provided a small swing typeexcavator, wherein the upper rotating body is mounted rotatably around avertical shaft on a lower traveling body, and wherein a working deviceis attached pivotedly at a front end of the upper rotating body,rotating radius of a rear end of the upper rotating body being set toabout one half of the width of the lower traveling body and devicesbeing mounted on a rotating frame of the upper rotating body,characterized in that a hydraulic pump, a power source and a coolingdevice are disposed laterally in a line as rear row devices in a rearsection of the rotating frame; and in front of the rear row devices, acontrol valve and a hydraulic oil tank are disposed in a line on onelateral side centering on a swivel joint, while a fuel tank is disposedon the other lateral side, the control valve, the hydraulic oil tank,and the fuel tank constituting front row devices.

In accordance with the above-described configuration, the hydraulicpump, the power source and the cooling device are disposed laterally ina line as rear row devices in the rear section of the rotating frame ofthe upper rotating body; and in front of the rear row devices, thecontrol valve and the hydraulic oil tank are disposed in a line on onelateral side centering on the swivel joint, while the fuel tank isdisposed on the other lateral side as front row devices, whereby thespace in the width direction of the rotating frame is used effectivelyin the small swing type excavator wherein a working device is attachedpivotedly at the front end of the upper rotating body, and major devicesare arranged in two lines from near the center of the rotating framethrough the rear section in the longitudinal direction. Consequently,the arrangement of pipes for the major devices is facilitated, andfurther the maintenance performance thereof is also improved.

Meanwhile, swinging motors have conventionally been arranged in thefront part of rotating frames. Hence, it is preferable that a swingingmotor be disposed between the swivel joint and the hydraulic oil tank.In this case, further space in the longitudinal direction is ensured tofacilitate the device layout.

It is preferable that an air conditioner be disposed between the swiveljoint and the fuel tank. In this case, an arrangement space for the airconditioner can be ensured to facilitate the layout thereof.

It is preferable that the fuel tank be arranged under the floor of anoperator cab disposed in the upper rotating body. In this case, anarrangement space for the fuel tank can be ensured to facilitate thelayout thereof.

In addition, it is preferable that the rear row devices be arrangedlaterally in the order of hydraulic pump, power source and coolingdevice, while the front row devices be arranged laterally in the orderof fuel tank, swivel joint, hydraulic oil tank and control valve, thefuel tank being arranged under the floor of an operator cab disposed inthe upper rotating body and the hydraulic pump being located in a rearside of the fuel tank. In this case, in addition to the advantage of thepresent invention as described above, it is possible to arrange a shortand simple return pipe for putting pressure oil from the control valveback to the hydraulic oil tank, whereby the back pressure of the controlvalve can be kept at low level. Generally, in the case of a high backpressure of control valve, the discharge resistance of pressure oilcauses heat generation and the back pressure is added to suppliedpressure from hydraulic pump, resulting in an increase in power requiredfor the hydraulic pump, which consequently runs counter to the saving ofenergy. Also, there is a possibility of having negative impacts on allaspects of the hydraulic pressure control circuit, such as a case thatdesired force cannot be obtained when operating each hydraulic actuator.Hence, in the present invention is used a short return pipe, whichenables the troubles above to be overcome.

Further, it is possible to dispose a suction pipe that communicates thehydraulic pump and the hydraulic oil tank and a delivery pipe thatcommunicates the hydraulic pump and the control valve between the rearrow devices and the front row devices almost linearly, whereby thearrangement of pipes is facilitated and pressure loss in the pipes canbe reduced. In particular, the suction pipe has a large diameter, andtherefore arranging the pipe with less number of bends has advantages interms of ensuring the easiness of the arrangement. In addition, althoughit is often the case that rotating frame is formed into a substantiallycircular shape to obtain as much an arrangement space for devices on theupper rotating body as possible, the size of the control valve isrelatively small, in accordance with the present invention, disposed onthe outside of the hydraulic oil tank that requires a large space,whereby the control valve can be arranged along the arc-shape of therotating frame, improving the usability of the space.

Furthermore, the fuel tank is arranged under the floor of the operatorcab, which allows effective use of the arrangement space for devices onthe upper rotating body. In addition, the hydraulic oil tank is arrangedbetween the floor of the operator cab and the control valve, whereby itis avoided that noises such as working oil flowing sound and restrictingsound from the control valve reach operators in the operator cab toreduce the comfort therein.

As described above, in accordance with the present invention, majordevices can be arranged effectively in a small swing type excavator witha small arrangement space for devices, providing a saving of energy atthe same time and also giving advantages in terms of controlling ahydraulic circuit, and further noises that may reach operators can belimited.

It is preferable that a battery be disposed on the outside of the fueltank in the lateral direction. In this case, it is possible to shortenthe arrangement space for devices longitudinally, giving advantages interms of forming a small swing type excavator in which the rear endthereof is within the vehicle width. Also, the battery, which requiresto be maintained appropriately, is arranged outside the fuel tank, whichfacilitates the maintenance of the battery as well as, for example whencleaning the fuel tank, the detachment of the fuel tank by detaching thebattery. In particular, since the fuel tank is less often maintainedthan the battery, the arrangement above is found to be effective.

It is preferable that an air conditioner be disposed over the floor ofthe operator cab, for example, under the operator seat, or in a cabin ifprovided for the operator cab. In this case, the space under the floorof the operator cab can be used more effectively, that is, for example,the volume of the fuel tank can be increased. Although small swing typeexcavators having a canopy, in which the space over the floor of theoperator cab is opened outward, include no air conditioner, the spaceunder the floor of the operator cab can be used effectively even in sucha case.

It is preferable that the suction pipe that communicates the hydraulicpump and the control valve be guided under the floor of the operatorcab, while a pilot pipe that communicates the control valve and a pilotvalve disposed over the floor of the operator-cab be guided over thefloor of the operator cab. In this case, an arrangement of the pipes inthe space under the floor of the operator cab can be formed simply.Also, it is possible to shorten the distance between the one closer tothe control valve of the pilot valve above, which are attached in anintegrated manner to operating levers that are provided, respectively,on the right and left sides of the operator seat, and the control valve,whereby the pilot pipe can be guided easily.

It is preferable that a swinging motor be disposed in front or rear ofthe swivel joint. In this case, the space between the hydraulic oiltank, which is enlarged longitudinally to increase the volume thereof,and the fuel tank can be used more effectively.

It is preferable that an oil filler port of the fuel tank be disposed inthe rear section thereof and above the hydraulic pump. In this case, itis possible to make effective use of the blank space over the hydraulicpump that is shorter in height than the cooling device.

It is preferable that an operation pattern switching valve for switchinga motion pattern of an actuator according to an operation of anoperation means among multiple motion patterns be disposed in front ofthe hydraulic oil tank. In this case, elements having switching portioncan be arranged around the control valve in a concentrated manner, whichmakes it possible to perform maintenance in a lump from the same place.

It is preferable that an operation lock valve for locking actuatorshydraulically to be inoperative be disposed in the vicinity of thehydraulic oil tank in front or rear of the control valve. Also in thiscase, elements having switching portion can be arranged around thecontrol valve in a concentrated manner, which makes it possible toperform maintenance in a lump from the same place.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing the overall construction of a small swing typeexcavator;

FIGS. 2A, 2B are schematic views showing the general structure under thefloor of a cabin of a small swing type excavator according to the firstembodiment of the present invention (with a fuel tank fixed), where FIG.2A is a horizontal sectional view, while FIG. 2B is a vertical sectionalview;

FIG. 3 is a horizontal sectional view showing the general structureunder the floor of the cabin of the small swing type excavator accordingto the first embodiment of the present invention (when removing the fueltank);

FIG. 4 is a perspective view showing the general structure of the fueltank according to the first embodiment of the present invention;

FIGS. 5A, 5B are schematic views showing the general structure under thefloor of a cabin of a small swing type excavator according to the secondembodiment of the present invention, where FIG. 5A is a horizontalsectional view, while FIG. 5B is a vertical sectional view;

FIG. 6 is a perspective view showing the general structure of the fueltank according to the second embodiment of the present invention;

FIGS. 7A, 7B are schematic views showing the general structure under thefloor of a cabin of a small swing type excavator according to the thirdembodiment of the present invention, where FIG. 7A is a horizontalsectional view, while FIG. 7B is a vertical sectional view;

FIGS. 8A, 8B are schematic views showing the general structure under thefloor of a cabin of a small swing type excavator according to the fourthembodiment of the present invention, where FIG. 8A is a horizontalsectional view, while FIG. 8B is a vertical sectional view;

FIGS. 9A, 9B are views showing a detailed structure of a rotating frameof a small swing type excavator according to the fifth embodiment of thepresent invention, where FIG. 9A is a horizontal sectional view, whileFIG. 9B is a vertical sectional view; and

FIGS. 10A, 10B are views showing the arrangement of the major pipes inFIGS. 9A, 9B where FIG. 10A is a horizontal sectional view, while FIG.10B is a vertical sectional view.

BEST MODE FOR CARRYING OUT THE INVENTION

Some embodiments of the present invention will hereinafter be describedwith reference to the accompanying drawings.

(a) FIRST EMBODIMENT

FIG. 1 shows the overall construction of a so-called small swing type orshort-radius excavator among various types of small hydraulicexcavators, in which the vehicle body of the short-radius excavatorconsists of a lower traveling body 1, an upper rotating body 2 mountedrotatably around a vertical shaft on the lower traveling body 1, anexcavating attachment not shown in the figure consisting of, forexample, a boom pivoted movably in the lateral direction at a supportmember of a working device that is provided at the front end of theupper rotating body 2 in a protruding manner, and a dozer 3 pivotedmovably in the vertical direction to the lower traveling body 1, etc.

The lower traveling body 1 consists of right and left crawler frames 4and crawlers 5 (only one side, respectively, thereof is shown in thefigure), the crawlers 5 on the both sides being driven rotationallyseparately by right and left traveling motors 7 to run the vehicle.

The upper rotating body 2 comprises a rotating frame 8, the rear endrotating radius of which being set to about one half or of the width ofthe lower traveling body 1, and a counterweight 9, on the rotating frame8 being mounted a cabin 83 having a substantially sealed structure toform an operator cab, an engine and devices such as a hydraulic pumpdriven by the engine, as will be described hereinafter.

The cabin 83 among the above-mentioned components is formed into a boxshape having a ceiling, front and rear walls, and right and left wallsas peripheral walls, and has the substantially sealed structure, whichis adapted to shut out outside air to protect operators against outsidenoise, dust, etc., wherein an air conditioner 85 is provided to ensurehabitability thereof.

The overall construction of this kind of short-radius excavator can beapplied similarly in the second to fourth embodiments describedhereinafter.

Continuously, the device layout in the rotating frame 8 thatcharacterizes the present first embodiment will be described in detailwith reference to FIGS. 2A and 2B. It is noted that the left side inFIG. 2A corresponds to front side, the right side to rear side, theupper side to right side, and the lower side to left side.

As shown in FIGS. 2A and 2B, the rotating frame 8 is formed into alittle flattened cylinder shape cutting off part of the front side, anda floor 84 (flat part under the operator cab) of the cabin 83 is formedsubstantially within the left half from the front side through thecentral portion (the floor 84 is represented by the dashed line in FIG.2A). The rotating frame 8 is set to be shorter longitudinally, while alittle longer laterally in comparison with common small hydraulicexcavators.

In the present first embodiment, there is provided an engine (referredto as E/G in FIG. 2) 81 as a power source mounted transversely with anoutput shaft thereof extending laterally in the rear section of therotating frame 8, a hydraulic oil tank (H/T likewise as above) 82disposed in front and right of the engine 81, the cabin 83 disposed infront and left of the engine 81, an air conditioner (A/C likewise asabove) 85 disposed on an inner side in the width direction of theexcavator in the space under the floor 84 of the cabin 83, and a fueltank (F/T likewise as above) 86 disposed on the outside of the airconditioner 85.

It is noted that the numeral 801 indicates a control valve (C/V likewiseas above), 802 a manipulation pattern switching valve (M/V likewise asabove), 803 a swinging motor. (S/M likewise as above), 804 a swiveljoint (S/J likewise as above), 805 a battery (BAT likewise as above),807 a hydraulic pump (P likewise as above), 808 a radiator (R/D likewiseas above), and 809 an oil cooler (O/C likewise as above).

The engine 81 is, for example, a diesel engine, wherein the hydraulicpump 807 is connected to one end of the output shaft, while a fan, notshown in the figure, is attached to the other end thereof to air-coolthe radiator 808 and the oil cooler 809.

The hydraulic oil tank 82 is a steel tank for storing hydraulic oil fromeach hydraulic device. Then, an oil filler port extends up to the outerperipheral wall of the rotating frame 8, although not shown in thefigure, which allows fueling of the tank. Also, an oil discharge portclosed with a cap is provided at a position where an operator can accessfrom under the rotating frame 8, and then remove the cap to recoverdischarge oil when performing maintenance.

In the air conditioner 85, while part of the unit (although there areincluded a condenser unit and an air conditioner unit, the former ishere ignored, the same applying hereinafter) protrudes inside a seatstand 87, most part of the unit is arranged under the floor 84 of thecabin 83 (the part arranged under the floor will hereinafter be referredto simply as the air conditioner 85).

The fuel tank 86 is a tank having a complicated shape that stores fuelfor the engine 81, which is made of, for example, plastics withremarkable workability. The fuel tank 86 is installed in the extremelynarrow space of under the floor 84 of the cabin 83 together with the airconditioner 85, and thereby has a flattened shape wholly that has notconventionally been able to allow for enough volume. Hence in thepresent first embodiment, the structure of the fuel tank 86 is adaptedto comprise an extension portion extending to at least the front surfaceside of the air conditioner 85, whereby an ever-larger volume can beensured.

To be more concrete, the fuel tank 86 consists of, as shown in FIG. 4, aceiling surface 86 a and a bottom surface 86 b formed into an L shape, afront surface 86 c, a left side surface 86 d, rear surfaces 86 e and 86f, and right side surfaces 86 g and 86 h formed into respectiverectangular shapes, the left side surface 86 g and the rear surface 86 fbeing arranged along, respectively, the left side surface and the frontsurface of the air conditioner 85. Even complicated shapes such as the Lshape above can be formed easily by means, for example, of injectionmolding if the tank is made of plastics.

Then, in front and right of the ceiling surface 86 a is provided asensor 863 to detect the amount of fuel in the fuel tank 86, and forexample, a warning light in the cabin 83 is to be turned on by receivinga signal from the sensor 863 when the fuel gets low.

The sensor 863 is formed with, for example, a float switch, which is tobe taken outside in an integrated manner with the tank when taking thetank outside as will be described hereinafter. Therefore, the sensor 863is connected to a guided wire in the rotating frame 8 through aconnector not shown in the figure. Then, the connector is to bedisconnected to take the tank outside.

Also, an oil filler port 865 closed with a cap 864 protrudes in rear andleft of the ceiling surface 86 a. The oil filler port 865 extends up tothe outer wall of the rotating frame 8, which makes it possible to fuelthe tank by removing the cap 864 in such a condition that the tank isinstalled in a predetermined position.

Further, a fuel suction port 866 is provided in an appropriate positionof the ceiling surface 86 a, the fuel suction port 866 being connectedto a guided pipe that leads to a fuel feeding device for the engine 81in the rotating frame through a joint not shown in the figure. Then, thejoint is to be disconnected to take the tank outside. It is noted thatit is preferable to provide the position of the fuel suction port 866 inthe vicinity of the center of rotation of the excavator as close aspossible to prevent air intake, even in the case of work on an inclinedsurface, which can be made responsive by giving a guided pipe suitablein the tank to the fuel suction port 866, unlike in the case of thesensor 863 above.

In the present first embodiment, the fuel tank 86 is detachably attachedto the rotating frame using, for example, a band not shown in thefigure, particularly in case of contamination of foreign materials intothe tank, where the fuel tank 86 can be taken outside the rotating frame8 by removing the band. Therefore, a holding part, etc. for taking thetank outside may be provided in an appropriate position of the fuel tank86.

Also in accordance with the above mentioned, in the rotating frame 8 isprovided an opening portion 861 having an area capable of taking thefuel tank 86 outside together with the sensor 863 in the take-outdirection of the fuel tank 86, as well as a cover portion 862 adapted tocover the opening portion 861 while not taking the tank 86 outside. Thecover portion 862 is made of steel, the same material as the outer wall,and is fastened with bolts around the opening portion 861 of the outerwall, while may be hinged openably to the opening portion 861 forexample.

Further, frictional force at the bottom of the fuel tank 86 in therotating frame 8 may be reduced to make it easy to take the tankoutside, and a sliding rail, etc. may be provided along the movementroute of the tank so that the tank is returned to the original positionthereof accurately again.

In addition to above, although on the rotating frame 8 are provided anindefinitely large number of guided pipes and guided wires to connecteach of the foregoing devices, the arrangement thereof is not shown inthe figure. However, it goes without saying that the arrangement of eachdevice is determined in such a manner that the length of the guidedpipes and guided wires is as short as possible.

The general procedure for maintenance of the fuel tank will hereinafterbe described.

As shown in FIG. 2A, the fuel tank 86 is arranged along two surfaces ofthe front and left side surfaces of the air conditioner 85, and there isfixed to the rotating frame 8 using the band above.

When performing maintenance, an operator first opens the cover portion862 of the rotating frame 8, and disconnect the connector of the sensor863 of the fuel tank 86 from the guided wire in the rotating frame 8through the opening portion 861 as well as disconnect the joint of thefuel suction port 866 from the guided pipe in the rotating frame 8, andthen removes the band fixing the fuel tank 86. Then, the fuel tank 86 ispulled toward this side in the figure from a fixed position on therotating frame 8 through the opening portion 861.

Next, a simple pump, etc. are connected to the joint of the fuel suctionport 866 of the fuel tank 86 taken outside to drain remaining fuelcompletely, and then the inside of the tank is cleaned with kerosene,etc. to remove foreign materials. Thus, impurities accumulated at thebottom of the fuel tank 86 can be removed.

After performing the steps above, the fuel tank 86 is returned to theoriginal position thereof by a reverse procedure to above and is fixedusing the band, and the connector of the sensor 863 of the fuel tank 86is connected to the guided wire in the rotating frame 8 as well as thejoint of the fuel suction port 866 is connected to the guided pipe inthe rotating frame 8, and then the opening portion 861 is closed withthe cover portion 862.

Thus, the fuel tank 86 may be detached from the rotating frame 8 to becleaned on the outside thereof before the engine 81 becomes inoperative(engine down), and then impurities accumulated at the bottom of the fueltank 86 can be removed to prevent engine down. Meanwhile, in theunlikely event that the engine goes down, the fuel tank 86 may bedetached from the rotating frame 8 to be cleaned on the outside thereof,and then impurities accumulated at the bottom of the fuel tank 86 canalso be removed to restart the operation of the engine 81. Also, it ispossible to make it unlikely by means of the cover portion 862 thatsediments may get inside around the fuel tank 86 through the openingportion 861, and to protect the fuel tank 86 against unexpected directhits by sediments, etc.

As explained above, in the present first embodiment, the cabin 83 isdisposed on one lateral side on the rotating frame 8 of the upperrotating body 2, and the air conditioner 85 and the fuel tank 86 areprovided, respectively, on an inner and an outer side in the widthdirection of the excavator in the space under the floor 84 of the cabin83, the fuel tank 86 comprising the extension portion extending to atleast the front surface side of the air conditioner 85, wherebyproviding the large-sized fuel tank 86 utilizing the blank space infront of the air conditioner 85 which has not been conventionally used,the volume of the fuel tank 86 may be increased with ensuring of anarrangement space for the air conditioner 85. Therefore, it is possibleto ensure the volume of the fuel tank 86 to increase the fuelinginterval, resulting in an improvement in operating efficiency.

It is noted that the fuel tank 86, although formed in an L shape whenviewed vertically and arranged along the front and left side surfaces ofthe air conditioner 85 in the first embodiment above, may be arrangedalong three surfaces of both the front and rear surfaces and the leftside surface in some cases (in these cases, the fuel tank is to beformed into a U shape when viewed vertically). Also, it will beappreciated that in the case the overall arrangement of the rotatingframe 8 above is reversed laterally, the fuel tank may be formed inaccordance with such arrangement (in this case, the fuel tank is to bearranged along the front (and rear) and left side surfaces of the airconditioner).

(b) SECOND EMBODIMENT

The device layout in a rotating frame 8 that characterizes the presentsecond embodiment will be described in detail with reference to FIGS. 5Aand 5B. It is noted that the left side in FIG. 5A corresponds to frontside, the right side to rear side, the upper side to right side, and thelower side to left side, and for the sake of convenience, the samenumerals are assigned to components in FIGS. 5A and 5B in common withthose in the first embodiment above.

The configuration of the rotating frame 8 shown in FIGS. 5A and 5B isthe same as that of the first embodiment. The floor 84 is represented bythe dashed line in FIG. 5A.

In the present second embodiment, an engine (E/G) 81 as a power sourceis disposed in the rear section of the rotating frame 8, though in alaterally stretched long attitude, in a slanted manner where both thelateral ends are longitudinally shifted each other so that thelongitudinal direction thereof is arranged at a predetermined angle withthe lateral center line of the rotating frame 8. Then, on the right endside (one end side) closer to the front side of the engine 8 in theslanted manner are disposed a radiator (R/D) 808 and an oil cooler (O/C)809 as cooling devices in this order outward, while on the left end side(the other end side) closer to the rear side than the right end side isprovided a hydraulic pump (P) 807. In front of the engine 81, there aredisposed a swinging motor (S/M) 803 and a control valve (C/V) 801 inthis order on the right side of a swivel joint (S/J) 804 arranged at thecenter of rotation of the rotating frame 8, while on the left sidethereof an air conditioner (A/C) 85 and a fuel tank (F/T) 86 in thisorder, and in the space (corresponding to the predetermined space)formed between the hydraulic pump 807 and the fuel tank 86 is disposed ahydraulic oil tank (H/T) 82. It is noted that the numeral 802 indicatesan operation or a manipulation pattern switching valve (M/V), while 805a battery (BAT). Here, the reason for arranging the devices centering onthe swivel joint 804 is that the fuel tank 86 and the control valve 801can be arranged separately close to the vicinity of the outer peripheralwall where the width of the rotating frame 8 is maximized, whereby thevolume of the fuel tank 86 can be ensured and the maintenanceperformance of the control valve 801 can be improved.

To the left end of an output shaft of the engine 81 that extendslaterally is connected the hydraulic pump 807.

The hydraulic oil tank 82 is formed into a fan shape in such a mannerthat the tank 82 spreads outward from the rotating frame 2 when viewedvertically so as to fit into the space between the hydraulic pump 807and the fuel tank 86, which is generated by arranging the engine 81 inthe slanted manner.

To be more concrete, the hydraulic oil tank 82 consists of, as shown inFIG. 6, a ceiling surface 82 a and a bottom surface 82 b formed into afan shape, a left side surface 82 d curved with a predeterminedcurvature along the outer wall of the rotating frame 8, a front surface82 c, a rear surface 82 e, and a right side surface 82 f formed intorespective rectangular shapes.

Meanwhile, as shown in FIG. 5B, there generally exists a space under thehydraulic pump 807, which may be further utilized. For example, aprojecting portion 821 can be provided at the left lower part of therear surface 82 e of the hydraulic oil tank 82 as shown by the two-dotchain line in FIG. 6. The projecting portion 821 has a height capable ofgetting under the hydraulic pump 807 and a geometry capable of having nocontact with the body of the engine 81. Thus, the maximum volume of thehydraulic oil tank 82 can be obtained. It is noted that depending on thearrangement of other devices in the rotating frame 8, the whole of thehydraulic oil tank 82 may be fitted into the space under the hydraulicpump 807.

Also, an oil filler port extends up to the outer peripheral wall of therotating frame 8, although not shown in the figure, which allows fuelingof the tank 82. Further, an oil discharge port closed with a cap isprovided at a position where workers can access from under the rotatingframe 8, and then remove the cap to recover discharge oil whenperforming maintenance.

In the air conditioner 85, while part of the unit protrudes inside aseat stand 87, most part of the unit is arranged under the floor 84 ofthe cabin 83 of the rotating frame 8.

An oil filler port of the fuel tank 86 extends up to the outerperipheral wall of the rotating frame 8, although not shown in thefigure, which allows fueling of the tank 86. It is easy to do the layoutof the fuel tank 86, due to the excellent workability thereof, even insuch a narrow space as under the floor 84 of the cabin 83 where the fueltank 86 is arranged together with the air conditioner 85. Then, otherdevices can be arranged high in the vehicle, whereby the layout isfacilitated.

In addition to above, on the right side of the rotating frame 8 isprovided an opening portion 811 having an area capable of maintainingthe control valve 801, the radiator 808 and the oil cooler 809, etc., aswell as a cover portion 812 adapted to cover the opening portion 811while not maintaining such devices. The cover portion 812 is made ofsteel, the same material as the outer wall, and is fastened with boltsaround the opening portion 811 of the outer wall, while may be hingedopenably to the opening portion 811 for example. Thus, devices can bemaintained easily if necessary by opening the cover portion 812.

As explained above, in the present second embodiment, the engine 81 isdisposed in the rear section of the rotating frame 8 in a laterallystretched long attitude and a slanted manner where both the lateral endsare longitudinally shifted, whereby it never occurs that most of thespace in the rear section of the rotating frame of the upper rotatingbody is occupied only by the engine 81. That is, although the shape ofthe engine 81 is determined almost automatically to meet the functionthereof, when arranging the engine 81 in such a slanted manner, acertain space can be ensured in front of one lateral side from where thepower source is moved backward away. In this case, it is possible, forexample, to dispose the fuel tank 86 having high-degree of freedom ofshape under the floor 84 of the cabin 83 installed in front of theengine 81, and to dispose the large-sized hydraulic oil tank 82 in theblank space ensured as above. Thus, it is possible to allow for thedevice arrangement in the rotating frame.

In addition, the hydraulic pump 807 is disposed on one end side closerto the rear side of both the lateral ends of the engine 81, while theradiator 808 and the oil cooler 809 are disposed on the other end sidecloser to the front side; the fuel tank 86 is disposed in front of thehydraulic pump 807 through the foregoing predetermined space; and thehydraulic oil tank 82 is disposed in this space, whereby the amount ofsuction pipes on the rotating frame 8 is reduced, and combined with theslanted arrangement of the engine 81, it is further possible to allowfor the device arrangement in the rotating frame 8.

It is noted that although the working oil tank 82 is formed into a fanshape when viewed vertically in the second embodiment above, it ispossible to adopt every kind of other shapes capable of realizing largevolume. Also, it will be appreciated that the overall arrangement of therotating frame 8 above may be reversed laterally and the fuel tank maybe formed in accordance with such arrangement.

Also, the swinging motor 803, although disposed between the controlvalve 801 and the swivel joint 804 in the second embodiment above, isnot necessarily a large-sized device, and thereby can be arranged inanother place.

Further, the air conditioner 85, although disposed between the swiveljoint 804 and the fuel tank 86 in the second embodiment above, is notrequired to be installed in such a case where no cabin 83 is provided,which further allows for the device arrangement.

Meanwhile, although in the first and second embodiments above, it is notnecessarily assumed that the working device is attached pivotedly in thelateral and longitudinal directions in a protruding manner from thefront end of the upper rotating body 2 in FIG. 1, the inventionaccording to the third to fifth embodiments described hereinafter isdirected to short-radius excavators in which a working device isattached pivotedly the lateral and longitudinal directions in aprotruding manner from the front end of the upper rotating body 2. Theembodiments will hereinafter be described.

(c) THIRD EMBODIMENT

The device layout in a rotating frame 8 that characterizes the presentthird embodiment will be described in detail with reference to FIGS. 7Aand 7B. It is noted the left side in FIG. 7A corresponds to front side,the right side to rear side, the upper side to right side, and the lowerside to left side, and for the sake of convenience, the same numeralsare assigned to components in FIGS. 7A and 7B in common with those inthe first and second embodiments above.

The configuration of the rotating frame 8 shown in FIGS. 7A and 7B isthe same as that of the first and second embodiments. The floor 84 isrepresented by the dashed line in FIG. 7A.

In the present third embodiment, a hydraulic pump (P) 807, an engine(E/G) 81, a radiator (R/D) 808, and an oil cooler (O/C) 809 are disposedin a line from the left to right side in this order as rear row devicesin the rear section of the rotating frame 8; and in front of the rearrow devices, a swinging motor (S/M) 803, a hydraulic oil tank (H/T) 82,and a control valve (C/V) 801 are disposed in a line in this order onthe right side of a swivel joint (S/J) 804, while on the left sidethereof an air conditioner (A/C) 85 and a fuel tank (F/T) 86 in a linein this order as front row devices. It is noted that the numeral 802indicates an operation or a manipulation pattern switching valve (M/V),while 805 a battery (BAT).

An oil discharge port of the hydraulic oil tank 82 closed with a cap isprovided at a position where an operators can access from under therotating frame 8, and then remove the cap to recover discharge oil whenperforming maintenance.

In the air conditioner 85, while part of the unit protrudes inside aseat stand 87, most part of the unit is arranged under the floor 84 ofthe cabin 83 of the rotating frame 8.

An oil filler port of the fuel tank 86 extends up to the outerperipheral wall of the rotating frame 8, although not shown in thefigure, which allows fueling of the tank.

As explained above, in the present third embodiment, the hydraulic pump(P) 807, the engine (E/G) 81, the radiator (R/D) 808, and the oil cooler(O/C) 809 are disposed in a line from the left to right side in thisorder as rear row devices in the rear section of the rotating frame 8 ofthe upper rotating body 2; and in front of the rear row devices, theswinging motor (S/M) 803, the hydraulic oil tank (H/T) 82, and thecontrol valve (C/V) 801 are disposed in a line in this order on theright side of the swivel joint (S/J) 804, while on the left side thereofthe air conditioner (A/C) 85 and the fuel tank (F/T) 86 in a line inthis order as front row devices, whereby the space in the widthdirection of the rotating frame 8 is used effectively in theshort-radius excavator in which a working device is attached pivotedlyat the front end of the upper rotating body 2, and major devices arearranged in two lines from near the center of the rotating frame 8through the rear section in the longitudinal direction. Consequently,the arrangement of pipes for the major devices is facilitated, andfurther the maintenance performance thereof is also improved.Additionally, arrangement spaces for the air conditioner 85 and the fueltank 86 can be ensured to facilitate the layout thereof.

(d) FOURTH EMBODIMENT

Meanwhile, in the third embodiment above, the rear row devices only maybe rotated by 180 degrees to be arranged against the front row devices.The present fourth embodiment, which has been made focusing on thispoint, will hereinafter be described with reference to FIGS. 8A and 8B.It is noted that the left side in FIG. 8A corresponds to front side, theright side to rear side, the upper side to right side, and the lowerside to left side, and for the sake of convenience, the same numeralsare assigned to components in common with those in the third embodimentabove to omit redundant descriptions as much as possible.

As shown in FIGS. 8A and 8B, in the present fourth embodiment, an oilcooler (O/C) 809 and a radiator (R/D) 808 as cooling devices, an engine(E/G) 81 as a power source, and a hydraulic pump (P) 807 are disposed ina line from the left to right side in this order as rear row devices inthe rear section of a rotating frame 8 of an upper rotating body 2; andin front of the rear row devices, a swinging motor (S/M) 803, ahydraulic oil tank (H/T) 82, and a control valve (C/V) 801 are disposedin a line in this order on the right side of a swivel joint (S/J) 804,while on the left side thereof an air conditioner (A/C) 85 and a fueltank (F/T) 86 in a line in this order as front row devices. It is notedthat the numeral 802 indicates an operator or a manipulation patternswitching valve (M/V), while 805 a battery (BAT).

The hydraulic oil tank 82, the air conditioner 85, the fuel tank 86,etc. are similar to those in the first embodiment above, and the sameapplies to the point that on the rotating frame 8 are provided anindefinitely large number of guided pipes and electric wires to connecteach of the foregoing devices.

In the present fourth embodiment, the hydraulic oil tank 82 is disposedimmediately in front of the hydraulic pump 807, and therefore the lengthof a suction pipe that communicates the hydraulic pump 807 and thehydraulic oil tank 82 is reduced. Since this suction pipe has a largediameter, facilitating the arrangement thereof gives a great advantage.The other configurations of the present fourth embodiment is the same asthose of the third embodiment above, and therefore it will beappreciated that the present fourth embodiment gives the same advantageas the third embodiment above.

It is noted that the configurations of the third and fourth embodimentsabove may be reversed laterally, and further the manipulation patternswitching valve 802 and the battery 805 may be included in thearrangement of the other devices.

Also, the swinging motor 803, although disposed between the swivel joint804 and the hydraulic oil tank 82 in the third and fourth embodimentsabove to ensure as large a space as possible in the longitudinaldirection, may similarly be excluded from the front row devices also inthis case.

Further, the air conditioner 85, although disposed between the swiveljoint 804 and the fuel tank 86 in the third and fourth embodiments aboveto ensure an arrangement space for the air conditioner 85 in theshort-radius excavator in which a working device is attached pivotedlyat the front end of the upper rotating body 2, may be excluded from thefront row devices in such a case where no cabin 83 is provided.

(e) FIFTH EMBODIMENT

The air conditioner 85, although disposed under the floor 84 of thecabin 83 in both the third and fourth embodiments above, may be disposedover the floor 84 of the cabin 83. The present fifth embodiment, whichhas been made focusing on this point, will hereinafter be described withreference to FIGS. 9A and 9B as well as FIGS. 10A and 10B. It is notedthat the left side in FIGS. 9A and 10A corresponds to front side, theright side to rear side, the upper side to right side, and the lowerside to left side, and for the sake of convenience, the same numeralsare assigned to components in common with those in the third and fourthembodiments above to omit redundant descriptions as much as possible.

As shown in FIGS. 9A and 9B, in the present fifth embodiment, ahydraulic pump (P) 807, an engine (E/G) 81 as a power source, and aradiator (R/D) 808 and an oil cooler (O/C) 809 as cooling devices aredisposed in a line from the left to right side in this order as rear rowdevices in the rear section of the rotating frame 8, as is the case withthe third embodiment above. In front of the rear row devices, ahydraulic oil tank (H/T) 82 and a control valve (C/V) 801 are disposedin a line in this order on the right side of a swivel joint (S/J) 804,while on the left side thereof a fuel tank (F/T) 86 as front rowdevices. It is noted that the numeral 85 indicates an air conditioner(A/C), 802 a manipulation pattern switching valve (M/V), 803 a swingingmotor (S/M), 805 a battery (BAT), and 810 a solenoid valve (S/V) as anoperation lock valve.

The battery 805 is disposed on the left outside of the fuel tank 86.Thus, it is possible to shorten the arrangement space for deviceslongitudinally, giving advantages in terms of forming a short-radiusexcavator in which the rear end thereof is within the vehicle width.Also, it is possible to facilitate the maintenance of the battery 805,as well as, for example when cleaning the fuel tank 86, the detachmentof the fuel tank 86 easily by detaching the battery 805. In particular,since the fuel tank 86 is less often maintained than the battery 805,the arrangement above is found to be effective.

The air conditioner 85 is arranged over the floor 84 of the cabin 83,for example, in a seat stand 87. Thus, the space under the floor 84 canbe used more effectively, that is, for example, the volume of the fueltank 86 can be increased. It is noted that the air conditioner 85 may bearranged at the ceiling part of the cabin 83, being not limitedparticularly within the seat stand 87. In this case, major devices canbe arranged under the floor 84, whereby the volume of the fuel tank 86can be increased.

The swinging motor 803 is arranged in front of the swivel joint 804.Thus, the space between the hydraulic oil tank 82, which is enlargedlongitudinally to increase the volume thereof, and the fuel tank 86 canbe used more effectively. It is noted that the swinging motor 803 may bearranged in rear of the swivel joint 804.

In order to ensure as much volume as possible, the fuel tank 86 isformed into an L shape when viewed vertically by depressing the partwhere the battery 805 is to be arranged at the left outer side in therotating frame 8. The hydraulic pump 807 is to be located in rear of thefuel tank 86. Then, an oil filler port 811 extends up to the outerperipheral wall of the rotating frame 8, which allows fueling of thetank. Thus, the blank space over the hydraulic pump 807 can be usedeffectively.

The manipulation pattern switching valve 802, which is adapted to switchthe motion pattern of actuators (not shown in the figure) for theoperation of an operating lever 815 (refer to FIG. 10B) as an operationmeans among multiple selective motion patterns, is disposed in front ofthe hydraulic oil tank 82.

The solenoid valve 810 is adapted to lock the foregoing actuatorshydraulically to be inoperative, the solenoid valve 810 being disposedin the vicinity of the hydraulic oil tank 82 in front of the controlvalve 801. Thus, elements having switching portions can be arrangedaround the control valve 810 in a concentrated manner, which makes itpossible to perform maintenance in a lump from the same place.

The arrangement of pipes in a configuration according to the presentfifth embodiment will be described.

As shown in FIGS. 10A and 10B, a suction pipe 812 that communicates thehydraulic pump 807 and the control valve 801 is guided under the floor84, while pilot pipes 813 that communicate the control valve 801 andpilot valves (P/V) 814 disposed over the floor 84 are guided over thefloor 84. In this case, an arrangement of the pipes in the space underthe floor 84 can be formed simply. Also, it is possible to shorten thedistance between the pilot valves 814, which are attached in anintegrated manner to operating levers 815 that are provided on operationboxes 817, respectively, on the right and left sides of the seat stand87, and the control valve 801, whereby the pilot pipes 813 can be guidedeasily.

It is noted that the numeral 815 is an operating lever adapted tooperate actuators in accordance with a desired motion pattern byswitching the manipulation pattern switching valve 802 in advance sothat the actuators operate in accordance with the desired motion patternamong multiple selective motion patterns. This allows operators tooperate actuators in accordance with desired motion patterns easily.

Also, the numeral 816 indicates an operation lock lever adapted to beoperated to turn the solenoid valve 810 on to close the pilot pipes 813.This allows actuators to be inoperative safely when operators get out ofthe cabin 83. However, a main pipe not shown in the figure may be closedinstead of the pilot pipes 813.

As explained above, in accordance with the present fifth embodiment, inaddition to the advantages of the third and fourth embodiments above, itis possible to arrange a short and simple return pipe (not shown in thefigure) for putting pressure oil from the control valve 801 back to thehydraulic oil tank 82, whereby the back pressure of the control valve801 can be kept at low level. Generally, in the case of a high backpressure of the control valve 801, the discharge resistance of pressureoil causes heat generation and the back pressure is added to suppliedpressure from the hydraulic pump 807, resulting in an increase in powerrequired for the hydraulic pump 807, which consequently runs counter tothe saving of energy. Also, there is a possibility of having negativeimpacts on all aspects of the hydraulic pressure control circuit, suchas a case that desired force cannot be obtained when operating eachhydraulic actuator. Hence, in the present fifth embodiment is used theshort return pipe, which enables the troubles above to be overcome.

Further, it is possible to dispose the suction pipe 812 thatcommunicates the hydraulic pump 807 and the hydraulic oil tank 82 and adelivery pipe (not shown in the figure, but can be guided along thesuction pipe) that communicates the hydraulic pump 807 and the controlvalve 801 between the rear row devices and the front row devices almostlinearly, whereby the arrangement of pipes is facilitated, and while thelength of the pipes is increased in comparison with the fourthembodiment above, pressure loss in the pipes can be reduced due to thelinear arrangement. In particular, the suction pipe 812 has a largediameter, and therefore arranging the pipe with less number of bends hasadvantages in terms of ensuring the easiness of the arrangement andreducing pressure loss. In addition, although it is often the case thatthe rotating frame 8 is formed into a substantially circular shape, asmentioned above, to obtain as much an arrangement space for devices onthe upper rotating frame 2 as possible, the size of the control valve801, in accordance with the present fifth embodiment, disposed on theoutside of the hydraulic oil tank 82 that requires a large space isrelatively small, whereby the control valve 801 can be arranged alongthe arc-shape of the rotating frame 8, improving the usability of thespace.

Furthermore, the fuel tank 86 is arranged under the floor 84, whichallows effective use of the arrangement space for devices on the upperrotating body 2. In addition, the hydraulic oil tank 82 is arrangedbetween the floor 84 of the cabin 83 and the control valve 801, wherebynoises such as working oil flowing sound and restricting sound from suchas flowing and squeezing sound the control valve 801 can be blocked outso as not to reach operators in the cabin 83 and not to reduce thecomfort therein.

It is noted that although in the fifth embodiment above is described acase where the cabin 83 installing the air conditioner 85 is provided,no air conditioner 85 is installed in short-radius excavators comprisinga canopy and opening the space over the floor 84 outward. Even in such acase, however, the space under the floor 84 can be used effectively byemploying the configuration in which major devices are arranged underthe floor 84 as described above.

Also, the solenoid valve 810 may be arranged in rear of the controlvalve 801, while the battery 805 may be arranged at the left end in rearside of the fuel tank 86, where depression of the fuel tank 86 is to beformed in accordance with the arrangement of the devices.

Further, although in the first to fifth embodiments above are describedcases where the engine 81 is used as a power source, ones other than theengine 81 may be used. In the case of using an electric motor as a powersource, for example, the radiator 808 as a cooling device becomesunnecessary. The radiator 808 and the oil cooler 809 may also bearranged on a single plane together.

Furthermore, it is possible to apply appropriate combinations of any ofthe first to fifth embodiments above. For example, the fuel tank 86comprising an extension portion that extends to the front surface sideof the air conditioner 85 in the first embodiment can be adopted to thesecond to fourth embodiments, and in this case, synergic advantages canbe offered.

Also, although in the first to fifth embodiments above are describedsmall hydraulic excavators as short-radius excavators, the presentinvention can also be applied to other short-radius constructionmachines.

INDUSTRIAL APPLICABILITY

As described above, the present invention is useful for a small swingtype excavator in which an upper rotating body rotates in such acondition that the rear end thereof hardly projects outside the width ofa lower traveling body, and is also suitable for a small swing typeexcavator in which a working device is attached pivotedly at the frontend of an upper rotating body.

1. A small swing type excavator, wherein an upper rotating body is mounted rotatably around a vertical shaft on a lower traveling body, rotating radius of a rear end of said upper rotating body being set to about one half of the width of said lower traveling body and devices being mounted on a rotating frame of said upper rotating body, comprising: an operator cab disposed on one lateral side on said rotating frame, an air conditioner and a fuel tank provided, respectively, on an inner and an outer side in the width direction of the excavator and in a space under a floor of said operator cab, wherein said fuel tank comprises an extension portion extending to at least the front surface of said air conditioner.
 2. The small swing type excavator according to claim 1, wherein said fuel tank is detachably attached to said rotating frame in such a condition that said extension portion extends along at least the front surface side of said air conditioner, and an opening portion capable of taking said fuel tank inside and outside therethrough is provided in an outer peripheral wall of said rotating frame.
 3. The small swing type excavator according to claim 2, further comprising a cover portion adapted to cover said opening portion and provided in the outer peripheral wall of said rotating frame.
 4. A small swing type excavator, wherein an upper rotating body is mounted rotatably around a vertical shaft on a lower traveling body, rotating radius of a rear end of said upper rotating body being set to about one half of the width of said lower traveling body and devices being mounted in a rotating frame of said upper rotating body, comprising: a power source disposed in a rear section of said rotating frame in such a manner that the length of said power source extends substantially laterally, wherein the length of the power source is inclined from the lateral direction such that the lateral ends of said power source are longitudinally shifted with respect to each other and one of the lateral ends is disposed closer to the rear of said rotating frame than is the other of the lateral ends; a hydraulic pump disposed at the one lateral end of said power source closer to the rear of said rotating frame; a cooling device disposed at the other lateral end of said power source; a fuel tank disposed in front of said hydraulic pump to be separated from said hydraulic pump by a predetermined space; and a hydraulic oil tank is disposed in said predetermined space.
 5. The small swing type excavator according to claim 4, wherein said fuel tank is disposed on one side of a swivel joint mounted at the center of rotation, while a control valve is disposed on the other side of the swivel joint, wherein said fuel tank and said control valve are in front of said power source.
 6. The small swing type excavator according to claim 4, wherein an operator cab is disposed on an upper surface of one lateral side of said rotating frame, and said fuel tank is arranged under a floor of said operator cab.
 7. The small swing type excavator according to claim 4, wherein said hydraulic oil tank is formed into a fan shape in such a manner that said hydraulic oil tank spreads to widen in a direction outward from said rotating frame when viewed vertically.
 8. The small swing type excavator according to claim 4, wherein said hydraulic oil tank is formed in such a manner that at least a part thereof reaches to under said hydraulic pump.
 9. The small swing type excavator according to claim 5, wherein said rotating frame comprises an opening portion for maintenance at the end on the side where said control valve and said cooling device are provided, and a cover portion adapted to cover said opening portion.
 10. A small swing type excavator, wherein an upper rotating body is mounted rotatably around a vertical shaft on a lower traveling body, and wherein a working device is attached pivotally at a front end of said upper rotating body, rotating radius of a rear end of said upper rotating body being set to about one half of the width of said lower traveling body and devices being mounted on a rotating frame of said upper rotating body, the rotating frame having a width which is substantially the same as that of said lower traveling body, the excavator comprising: a support member for the working device protruding from the front end of said upper rotating body a hydraulic pump, a power source and a cooling device disposed laterally in a line as rear row devices in a rear section of said rotating frame; in front of said rear row devices, a control valve and a hydraulic oil tank laterally disposed in a line on one lateral side centering on a swivel joint; and a fuel tank and a battery laterally disposed on the other lateral side, said control valve, said hydraulic oil tank and said fuel tank constituting front row devices, wherein the fuel tank is disposed between the battery and the swivel joint, and wherein the battery is disposed in a concave part of the fuel tank and outward of the fuel tank.
 11. The small swing type excavator according to claim 10, wherein a swinging motor is disposed between said swivel joint and said hydraulic oil tank.
 12. The small swing type excavator according to claim 10, wherein an air conditioner is disposed between said swivel joint and said fuel tank.
 13. The small swing type excavator according to claim 10, wherein said fuel tank is arranged under a floor of an operator cab mounted on said upper rotating body.
 14. The small swing type excavator according to claim 10, wherein said rear row devices are arranged laterally in the order of hydraulic pump, power source and cooling device, while said front row devices are arranged laterally in the order of fuel tank, swivel joint, hydraulic oil tank and control valve, said fuel tank being arranged under a floor of an operator cab mounted on said upper rotating body and said hydraulic pump being located in a rear side of said fuel tank.
 15. The small swing type excavator according to claim 14, wherein an air conditioner is disposed over the floor of said operator cab.
 16. The small swing type excavator according to claim 14, wherein a suction pipe that communicates said hydraulic pump and said control valve is guided under the floor of said operator cab, while a pilot pipe that communicates said control valve and a pilot valve disposed over the floor of said operator cab is guided over the floor of said operator cab.
 17. The small swing type excavator according to claim 14, wherein a swinging motor is disposed in front or rear of said swivel joint.
 18. The small swing type excavator according to claim 14, wherein an oil filler port of said fuel tank is disposed in the rear section thereof and above said hydraulic pump.
 19. The small swing type excavator according to claim 14, wherein an operation pattern switching valve for switching a motion pattern of an actuator according to an operation of an operation means among multiple motion patterns is disposed in front of said hydraulic oil tank.
 20. The small swing type excavator according to claim 14, wherein an operation lock means for locking actuators hydraulically to be inoperative is disposed in the vicinity of said hydraulic oil tank in front or rear of said control valve. 